[e.cash_v2] Improve chronik-client code snippets on landing page

Summary: Put in some scripts that might actually be used

Test Plan: proofread, build in CI, check it out

Reviewers: #bitcoin_abc, johnkuney

Reviewed By: #bitcoin_abc, johnkuney

Subscribers: johnkuney

Differential Revision: https://reviews.bitcoinabc.org/D18726